I have a CC6400 and I'm looking for a way to use the canned algo's to control a 2 stage gas furnace (DO only) and also be able to reset the SAT based on OAT...Any suggestions? I was hoping that the DO-DX Staging VAV Algo could be used by reversing the logic but it does not appear to be an option. Thanks in advance!

12-11-2012, 11:56 AM

junegemini

Is your control logic wants to be when OAT and SAT drops then cut in DO? or OAT rise then cut out DO?

12-11-2012, 05:34 PM

xornelasx

Quote:

Originally Posted by junegemini

Is your control logic wants to be when OAT and SAT drops then cut in DO? or OAT rise then cut out DO?

Junegemini: I need the DO's to maintain SAT setpoint by opening or droping when sthe SAT rises. I also need the SAT setpoint to reset based on OAT. In a nutshell I would like the Algorithm to behave exactly like the "DO- DX Staging VAV" but for a heat application. I've been trying to piece one together using the other canned algo's without any luck. I don't know Best++, otherwise I would go that route. Thanks!

12-12-2012, 12:20 PM

MrCarrier

Try changing your proportional term to a postive number instead of negative. Default for DO DX Staging VAV is -5, change it to a postive 5 and it should reverse the logic. Not 100% sure this will work for this algorithm but it does for other adaptive algoritms, and is worth a shot.

12-12-2012, 01:37 PM

junegemini

Quote:

Originally Posted by xornelasx

Junegemini: I need the DO's to maintain SAT setpoint by opening or droping when sthe SAT rises. I also need the SAT setpoint to reset based on OAT. In a nutshell I would like the Algorithm to behave exactly like the "DO- DX Staging VAV" but for a heat application. I've been trying to piece one together using the other canned algo's without any luck. I don't know Best++, otherwise I would go that route. Thanks!

Create one Analog SW pt unit %. Create an AO-Adaptive Control unit dC and use SAT as control sensor and OAT as reset sensor, then follow by two DO-Analog Comparison one for DO1 & the other for DO2 with the Analog SW pt in % as control sensor. Create two setpoints for the DO-Analog Comparison respectively. assume that your 1st DO-Analog Comparison will cut in 0~50% and the 2nd DO-Analog Comparison cut in 51~100%. just adjust the setpoint accordingly. Not sure this can help. Of course using BEST++ will be much more flexible. If you need guide please drop me a mail.